Girdling for Enhancing Morphogenetic Potential of Temperate Fruits: A Review

Manipulation of the source–sink relationship through bark incision is an ancient practice that considerably restricts vegetative growth and subsequently improves fruit production. Girdling intends making an incision of different thickness into the phloem entirely circumscribing the trunk. It inhibits the movement of photosynthates from source to the area below the plant parts from where phloem has been removed. Thereby carbohydrate accumulation and gas exchange are reduced due to feedback inhibition of photosynthesis above the girdled portion. Consequently, plant roots become devoid of photosynthates which results in the reduction of root metabolism that substantially reduces growth and development of both roots and shoots. This methodology is extremely effective controlling vegetative growth, enhancement of fruit yield, and quality attributes in horticultural crops. Duration and time of girdling can have profound effect on plant metabolic reactions, sometimes leading to undesirable outcomes. Additionally, the healing process after girdling plays a crucial role in minimizing any potential damage to the tree and ensuring its recovery. Despite being utilized for many centuries, the precise impact of girdling on plant metabolism still remains unclear. The review provides a concise overview of the girdling procedure, its mechanism, the healing process, and its effect on tree stature, flowering, fruit yield, and quality in temperate fruit crops.